Cement stabilized aggregate is also called cement stabilized graded aggregate, which can be referred to as cement aggregate or cement stabilized graded macadam for short. The so-called aggregate is a mineral aggregate mixture composed of crushed stone (or gravel), sand particles and powder (and sometimes clay particles), which is mainly composed of crushed stone (or gravel) and sand particles, and is collectively called aggregate. Aggregate usually refers to graded crushed stone or graded gravel without cohesive soil in the mixture. At present, the cement stabilized macadam used at the grass-roots level is a material that mixes the graded macadam with the maximum particle size of 20mm with a proper amount of stone powder, adds cement and water, and achieves the strength requirements after compaction and maintenance.

2.2 Factors affecting the quality of cement stabilized granular materials

(1) The strength of granular materials (the compressive capacity of crushed stones in cement stabilized granular materials) and the influence of gradation on the strength;

(2) The influence of cement properties and delay time on the strength and compactness of cement stabilized granular materials;

③ Influence of curing conditions and curing temperature.

2.3 Construction of cement stabilized granular materials

(1) Mechanical equipment shall adopt forced mixer or other mixing machinery, and the performance of the equipment shall match that of paving and rolling. Textile Road Mixer adopts two JS50 forced mixers.

(2) When mixing, strictly control the water content and cement dosage of cement stabilized aggregate, and record the weight ratio of each plate in detail. When there is deviation, immediately calibrate the electronic scale to achieve an accurate proportion.

(3) Due to the construction of textile road in summer, considering the moisture evaporation caused by climatic conditions, transportation distance, paving and rolling time and other factors, the water consumption should be appropriately increased when mixing; In order to ensure the paving of water-stable materials, 10 dump truck is used to transport them to the site to ensure that the water content of water-stable materials meets the requirements of optimal water content during paving and rolling.

2.4 cement stabilized aggregate laying

(1) Cement stabilized macadam is paved with paver.

(2) Loose paving thickness: The compaction coefficient and loose paving thickness shall be determined by pressure test according to the design of paving layer and required dry density, and the loose paving coefficient is 1.35.

(3) For the old pavement reconstruction project, before the formal construction of the cement stabilized layer, the lower bearing layer should be leveled and the water stabilized material should be rolled (it can be repaired in sections) to master and control the design elevation and smoothness of the water stabilized layer.

(4) in the process of paving, attention should be paid to prevent coarse aggregate from being concentrated due to the segregation of water-stable materials. When "holes" or "bands" appear, they should be removed in time and filled with fresh water-stable materials. When the mechanical paving operation surface is not enough, artificial hanging line paving should be adopted.

2.5 Integer of cement stabilized aggregate

(1) When the shop is paved manually, it should be paved at the same time, and the arch plate or stay wire should be used for preliminary paving;

(2) When paving mechanically, the grader shall be used for shaping;

(3) Immediately after paving, it shall be quickly rolled 1 pass on the already leveled road section to expose the potential unevenness. For local low-lying areas, rake the surface to a depth of more than 5 cm with a tooth rake, and repair and level it with fresh mixture. At the same time, check whether there is a "nest" or "band" of coarse aggregate, and remove and fill it according to the above method.

2.6 water-stabilized aggregate rolling

(1) Make a rolling plan according to the width of the road surface, the wheel width and the wheel distance of the road roller, and the rolling times of each part shall be the same as far as possible, and the two sides of the road surface shall be pressed for 2~3 times more.

(2) After molding, when the water content of the water-stable material is the optimal water content (+1% ~ +2%), it shall be immediately rolled with a light roller within the full width of the structural layer. Straight lines and curved lines without superelevation shall be rolled from the shoulders on both sides to the center of the road; The wheel width should overlap 1/2, and the rear wheel must exceed the joint of two sections. The full width of the road surface after the rear wheel is rolled is 1 time. After being crushed twice with a light roller, it is recompressed with a heavy roller. Generally, it needs to be rolled for 6~8 times, and the rolling speed of the roller is 1.5km/h~ 1.7km/h for the first two times, and then it is 2.0 km/h ~ 2.5 km/h.

(3) It is forbidden for the roller to turn around or brake suddenly on the completed or rolling section, and ensure that the surface of the water-stable layer is not damaged.

(4) In the process of rolling, the surface of cement stabilized layer should always be moist. If the water evaporates too fast, a small amount of water should be added in time, but it is forbidden to sprinkle water to crush it.

⑤ In the process of rolling, if there are "spring", looseness, peeling, etc., it should be turned over in time to mix again (adding proper amount of cement) or treated by other methods to meet the quality requirements.

⑥ After the cement stabilized layer is mixed and shaped, it should be rolled within the delay time determined by the test before the initial setting of cement, so as to achieve the required compactness and no obvious wheel tracks.

⑦ Before the end of rolling, the grader shall level again 1 time to make it comfortable longitudinally, and the road arch and elevation meet the design requirements. The final leveling should be carefully carried out, and the local higher part must be scraped off and the road cleared; For local low-lying areas, it is no longer necessary to repair, and it can be left to be treated when paving asphalt surface or concrete surface.

2.7 Treatment of transverse joints and longitudinal joints of cement stabilized macadam

(1) When paving water-stable materials, it should not be interrupted. If the interruption time exceeds 2h for any reason, a transverse joint shall be set.

(2) Manually tidy up the water-stable materials with appropriate water content at the end, and put two square timber close to the water-stable materials, the height of which should be the same as the compaction thickness of the water-stable materials, and level the water-stable materials close to the square timber (steel formwork can also be used instead of the square timber).

(3) The other side of the square wood (or steel formwork) is backfilled with sand or gravel, with a backfilling length of 3m and a height of several centimeters higher than that of wood (steel formwork).

(4) Compacting water-stable materials.

⑤ Before resuming the laying of water-stable materials, the sand and stone and the square timber (steel formwork) should be removed, the lower roof should be cleaned, and then the laying and rolling should be resumed.

⑥ If the transverse joints are not treated according to the above methods after paving interruption, and the interruption time exceeds 2h, the compacted and elevation-conforming end shall be dug into a section perpendicular to the road centerline and downward, and then new water-stable materials shall be paved again.

⑦ When the longitudinal treatment is transverse to the previous construction, the side near the center is supported by square timber or steel formwork, and the height of the square timber or steel formwork is the same as the compaction thickness of the water-stable layer.

⑧ After curing, remove the supporting wood (or board) before laying another one.